BMW M5 F90 (S63TU4): Engine Issues & Prevention Guide
"Every luxury car has a weak point. This guide identifies the BMW M5 F90's specific failure patterns, so you know exactly what to inspect before buying Eand what to budget for after."
Engine
7/10
Gearbox
7/10
Electric
6/10
Total Risk
4/10
Quick Verdict
Buy with CautionExpect significant running costs. Manageable if preventative maintenance is done.
Reliability Verdict
The F90 M5 (S63TU4) is the most reliable M5 in a generation. BMW fixed the S63TU's rod bearing vulnerability with revised clearances and a quasi-dry-sump oiling system. The main documented risk is the LPFP recall —hich BMW must complete for free. Expansion tank and coil packs are the typical wear items. Stock, well-maintained F90s have shown strong durability approaching 100k miles.
In This Guide
BMW M5 F90 Reliability: Is the S63TU4 Finally Fixed?
The BMW M5 F90 (2018 E23) is the most technologically advanced M car ever built. All-wheel drive. 600 horsepower. Rear-drive mode. A dual-clutch transmission and the revised S63TU4 engine.
It is also, critically, the most reliable M5 since the E39.
The F10 M5 era (S63TU) scarred the M community with BMW M5 Reliability & Real Costs anxiety and injector failures. Has BMW fixed it?
Yes —ostly. Here is the complete analysis.
1. What Changed on the S63TU4 (vs S63TU)
BMW did not simply bolt bigger turbos onto the old S63TU. The TU4 is a substantial revision:
- Revised BMW M5 Reliability & Real Costs: Wider clearances, improved metallurgy. The catastrophic clearance-related failure mode of the S63TU is dramatically less likely.
- Solenoid Injectors: The piezo injectors (the “Index 11 washout” risk) are gone. Solenoid units are used instead, with a much lower failure rate.
- Quasi-Dry-Sump Oiling: The F90 M5 uses a reservoir-assisted oil system similar to race cars. Under high G-loads or track use, oil starvation at the crank is prevented.
- Better Intercooling: Revised intercooler routing improves charge air cooling, reducing heat-related stress.
The result: Bimmerpost’s F90 reliability thread —ne of the largest in BMW forums —hows multiple owners with 2018 E21 M5s and zero major engine failures.
2. The LPFP Recall: The F90’s One Big Weakness
The Low-Pressure Fuel Pump (LPFP) is the known Achilles heel of the F90 M5 and G-generation BMWs.
The Problem
The LPFP impeller (plastic) can crack under thermal stress or fuel quality variation. When it does:
- The engine may stall at speed.
- Hard starts or no-starts occur.
- Fuel pressure drops below threshold and the engine goes into limp mode.
BMW’s Response
BMW issued a safety recall (23V-625 in the US) covering multiple models including the F90 M5. The pump must be replaced at no cost to the owner.
Action Required
- Check your VIN at NHTSA.gov for open recalls.
- If the recall is open, schedule immediately —his is a safety issue.
- If you are buying a used F90 M5, verify the recall is closed/complete in the service history.
3. Coolant Expansion Tank
The expansion tank on the S63TU4 is plastic and susceptible to cracking, particularly around the cap seat and the lower seam.
- Symptom: Low coolant warning, visible coolant residue (white powder) around the cap.
- Risk: If not addressed, the car will slowly lose coolant. An empty system causes catastrophic overheating.
- Fix: Replace tank. $200 E00 part + $200 labor. Do not ignore this.
4. Year-by-Year Reliability (2018 E23)
| Year | Engine | Known Issues | Reliability |
|---|---|---|---|
| 2018 | S63TU4 | LPFP (Recall), early software calibration issues | Good |
| 2019 | S63TU4 | LPFP (Recall), minor iDrive bugs | Good |
| 2020 | S63TU4 | LPFP (Some), Competition Pack power delivery | Very Good |
| 2021 | S63TU4 | LPFP (Later batch), coolant tank | Very Good |
| 2022 | S63TU4 | Minimal reports; latest calibration | Excellent |
| 2023 | S63TU4 | Too new for long-term data | Excellent (projected) |
5. Maintenance & Running Costs
| Service | Interval | Cost (Dealer) | Cost (Indie) |
|---|---|---|---|
| Oil Change (5W-40) | 5,000 miles | $400 | $200 |
| Spark Plugs | 20,000 miles | $800 | $600 |
| Brake Service (Front) | 20,000 E,000 miles | $2,500 | $1,500 |
| Transmission Fluid | 30,000 miles | $900 | $600 |
| Annual Total | E$3,500 E,000 | $2,000 E,500 |
6. Buying Guide
- Best Year to Buy: 2020 E22. LPFP recall mostly complete, software mature.
- CPO vs Used: CPO F90s give BMW warranty coverage. Given potential for cooling/fuel system issues, the CPO premium is worth it.
- Mileage Sweet Spot: 20,000 E,000 miles. Still under or near BMW’s Limited Warranty threshold for used vehicles.
- Avoid: Heavily tuned examples with upgraded turbos or high-boost maps. These cars stress the bottom end beyond the TU4’s improvements.
Related Resources
- BMW S63 Engine Reliability: Complete Guide
- BMW M8 F92 Ownership Cost
- BMW M5 vs Audi RS7 Reliability & Real Costs
The Reality Layer: What Owners Underestimate
Buying BMW M5 F90 is often driven by emotion, but keeping it on the road requires cold, hard logic. The dealership service center will not volunteer this information, but specialist independent mechanics know the truth:
- The Component Labor Trap: Engineering density means simple parts (sensors, plastic coolant fittings) require days of labor to reach. A $50 part often results in a $3,000 labor bill.
- The “Lifetime Fluid” Myth: Manufacturers claim transmissions and differentials use “lifetime” fluids to keep estimated maintenance costs artificially low for the first owner. To avoid a $10,000+ rebuild, you must change these fluids every 40,000 miles.
- Cascading Failures: When an air suspension strut leaks, the compressor burns out trying to keep the car level. Ignoring a warning light for 48 hours on a BMW can easily double the final repair invoice.
Caution
The Worst-Case Scenario: If you suffer a catastrophic failure without a comprehensive warranty or a dedicated $10,000+ emergency repair fund, you will be forced to sell the vehicle mechanically totaled at a massive loss.
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The Final Decision: Worth It?
Worth it if:
- You have a trusted, brand-specialized independent mechanic.
- You maintain a strict $5,000-$10,000 liquid repair reserve.
- You value the driving experience over strict financial rationality.
Not worth it if:
- You are stretching your budget just to afford the purchase price.
- You rely exclusively on the dealership network for out-of-warranty maintenance.
- You expect Toyota-like reliability and predictable ownership costs.
Related Intelligence
Executive Buying Advice
Verify the LPFP recall has been completed at a BMW dealer. Check the coolant expansion tank for hairline cracks (white residue around the cap). Avoid heavily tuned examples —he S63TU4 handles more power than the TU, but high-boost tunes still stress the bottom end.
